DIAGNOSIS OF DIAPHRAGMATIC TRAUMA WITH HELICAL CT IN A SWINE MODEL

OBJECTIVE. The purpose of this study was to determine whether diaphrag matic injury can be accurately diagnosed with helical CT in a swine mo del. The hypothesis of our study was that thin-section helical CT with sagittal and coronal reformations can reliably detect injury of the d iaphragm. MATERIALS AND METHODS. The study was performed in a swine mo del because of the similarity of the swine thorax to the human thorax. Ten swine had a limited abdominal helical CT (enteral contrast; 3-mm collimation; pitch, 1) before and after surgical creation of a 6-cm po sterolateral laceration in the left hemidiaphragm. A repeat scan was o btained after 5 cm of gastric fundus was sutured through the laceratio n. The gastric fundus was used because it is the most commonly herniat ed viscus in human diaphragmatic injury. No IV contrast was used. Cont rol, laceration, and herniation scans were reconstructed with 1.0-mm o verlap and reformatted in axial, sagittal, and coronal planes. Three o bservers scored each reformation as control or injury (defined as lace ration or herniation) in a blinded and randomized fashion. RESULTS. Us ing helical CT, the observers were able to distinguish diaphragmatic i njury from controls (p < .0001). The sensitivity and specificity were 92% and 87%, respectively, for sagittal reformations; 85% and 87%, res pectively, for coronal reformations; and 73% and 80%, respectively, fo r axial reformations. Sagittal reformations proved superior to coronal or axial reformations (p = .01). The results were independent of indi vidual observers: We found no significant difference in accuracy among the three observers. CONCLUSION. Helical CT can accurately detect dia phragmatic injury in a swine model.